I have been interested in the 2501 for quite a while now. Sorry no first hand experience with the 300 but here is my take on the subject.
The 2501 is an off-shore fishing machine. I feel because of that 90% of the ones I see in the for sale adds and in person have twin 200s. I was told by one gent down in Houston that he wouldn't consider anything less then 200s on his. He had twin 200 HPDI on his. This is strange because many of the SC models, that are much heavier then the CC, have twin 150s.
Basically I think it boils down to how you use your boat and what you expect of it. Will 300hp plane and efficiently cruise a loaded down 2501, sure. Will it respond and cruise as fast as twin 200hp+, no it won't. Different options for different needs I guess.
Along with the new 300 there is the F350 too. If you compare the performance bulletins the F350 campares favorably to the twin 150s. Faster and higher cruise mpgs, a little weeker out of the hole.